1. FIELD OF THE INVENTION
The present invention pertains generally to the filling of implanted infusion apparatuses, and more particularly to an implantable infusion apparatus, an apparatus for filling the infusion apparatus, and a method for accomplishing such filling.
2. DESCRIPTION OF THE CONTEMPORARY AND/OR PRIOR ART
The desirability of being able to implant a medication infusion pump in a human or animal body has been recognized by prior and contemporary technology. Patents such as U.S. Pat. No. 4,077,405, U.S. Pat. No. 4,033,479, and U.S. Pat. No. 4,073,292 recognize the desirability of dispensing medication from within the body. Where medication can be dispensed or infused directly to that portion of the body at which the medication is to be applied, lower concentrations of the medication and diminished side effects can be realized.
To achieve longer life for such implantable infusion apparatuses as well as for infusion apparatuses maintained external to the body, a feature of refillability has been suggested by both the prior and contemporary art. Summers, in U.S. Pat. No. 3,527,220, discloses a pump for administering drug to a body wherein the pump has a "self-sealing" port through which the pump can be filled with an appropriate drug. Similarly, Tucker et al and others in U.S. Pat. Nos. 3,951,147 and 4,193,397 discuss the periodic refilling of an infusate pump by injecting drug through an inlet septum into a storage chamber implanted beneath the skin. Likewise, Ellinwood, in U.S. Pat. Nos. 3,692,027, 3,923,060, 4,003,379, and 4,146,029, discloses a cylindrical inlet through which medication in a dispensing apparatus can be replenished. Similarly, Blackshear, in U.S. Pat. No. 3,731,681, discloses an inlet which is closed by means of a self-puncture sealing refill stopper. An invention of Blackshear (U.S. Pat. No. 3,731,681) shows another infusion pump wherein drug is fed through a self-sealing plug into an infusate chamber. Such prior and current apparatuses generally disclose the use of a resealable, or self-sealing, septum through which a drug refilling hypodermic needle can pass.
Another implanted device for supplying medicines is disclosed in U.S. Pat. No. 3,894,538 which provides for refillability through spring valves.
Those working with implant technology have also recognized the problem of bacteria flowing from a medication infusion pump into the body. Tucker, in U.S. Pat. No. 3,951,147, addresses this problem by first sterilizing the pump taught therein before implantation and by providing an outlet filter intended to trap air bubbles and debris.
Another problem heretofore unsolved by the prior art is associated with the necessity to refill a medication reservoir under pressure. If the portion of the refilling apparatus which enters the reservoir is not properly placed, a potentially fatal dose of medication can be injected directly into the patient in which the device is implanted.
These various inventions have underscored the benefit and advantages of designing an implantable medication device to be refillable. However, the above-cited technology fails to disclose various features which might render such a refillable implantable device safer, more convenient, and improved in operation.